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XSLPsetcbslpnode

Purpose
Set a user callback to be called during MISLP after the SLP optimization at each node.
Synopsis
int XPRS_CC XSLPsetcbslpnode(XSLPprob prob, int (XPRS_CC *slpnode) (XSLPprob cbprob, void *cbdata, int *p_infeasible), void *data);
Arguments
prob 
The current SLP problem.
slpnode 
The function to be called after the SLP optimization at a node. slpnode returns an integer value. If the return value is nonzero, or if the feasibility flag is set nonzero, then further processing of the node will be terminated (it is declared infeasible).
cbprob 
The problem passed to the callback function.
cbdata 
The user-defined object passed as data to XSLPsetcbslpnode.
p_infeasible 
Address of an integer containing the feasibility flag. If slpnode sets the flag nonzero, the node is declared infeasible.
data 
Address of a user-defined object, which can be used for any purpose by the function. data is passed to slpnode as cbdata.
Example
The following example sets up a callback function to be executed at each node after the SLP optimization finishes. If the solution value is worse than a target value (referenced through the user object), the node is cut off (it is declared infeasible). 
double OBJtarget;
XSLPsetcbslpnode(prob, CBSLPNode, &OBJtarget);
A suitable callback function might resemble the following: 
int XPRS_CC CBSLPNode(XSLPprob cbprob, void *Obj, int *p_infeasible) {
  double TargetValue, LPValue;
  XSLPgetdblattrib(prob, XPRS_LPOBJVAL, &LPValue);
  TargetValue = * (double *) Obj;
  if (LPValue < TargetValue) *p_infeasible = 1;
  return 0;
}
Further information

If a node can be cut off by the callback function, then further exploration of the node is avoided.


Related topics
XSLPsetcboptnode, XSLPsetcbprenode

Parent Topic Library functions

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